Improved solid particulate detergent compositions



IMPROVED SOLID PARTICULATE DETERGENT COMPOSITIONS Allen H. Lewis and Richard D. Stayner, Berkeley, Calif, assignors to California Research Corporation, San Francisco, Calif, a corporation of Delaware No Drawing. Application September 14, 1951, Serial No. 246,707

7 Claims. 01. 252-161) The present invention relates to improvements in solid particle-form detergent compositions. More particularly, it relates to the reduction and suppression of caking tendencies of solid particle-form detergent compositions which contain in each 100 parts by weight thereof from to 95 parts by weight of sodium salts of alkyl benzene sulfonic acids having from 9 to 18 carbon atoms in the alkyl chain as the active detergent ingredient, the remainder being essentially inorganic sodium salt builders.

Steadily increasing sales of solid particle-form alkyl benzene sulfonate-type detergents, i. e., synthetic detergent compositions containing as their active detergent ingredient salts of alkyl benzene sulfonic acid, bear proof of their successful application in a variety of household uses where heretofore soap has been employed. Most frequently the active ingredients of these detergent compositions are sodium monoalkyl benzene sulfonates with the alkyl chain containing from 9 to 18 carbon atoms.

Notwithstanding increasing general sales, the acceptance of these detergent compositions by the users residing in the hot and humid regions has been heretofore greatly handicapped by a tendency of these compositions to cake while stored in the conventional cardboard containers of the retail trade. 7

We have now found that the degree of caking of particle-form solid detergent compositions containing sodium C9 to 18 monoalkyl benzene sulfonate as their primary detergent ingredient can be reduced markedly by incorporating therein from about 0.5 to about 10.0% by weight of sodium salts of saturated aliphatic sulfonic acids containing from 1 to 6 carbon atoms in the aliphatic portion thereof, based on the weight of the composition including detergent and builder ingredients. The term saturated aliphatic sulfonic acid as employed in this specification includes both alkane sulfonic and cycloalkane sulfonic acids.

The active alkyl benzene sulfonate ingredient of the detergent compositions which can be rendered resistant to caking in accordance with the present invention may be produced in a number of ways. Very efficient C9 to C18 monoalkyl benzene sulfonate detergents are prepared, for instance, by alkylating benzene with a long-chain olefin or an olefin polymer containing from 9 to 18 carbon atoms. The resulting C9 to C18 alkyl benzene product, and preferably a fraction thereof .containing from 12 to 15 carbon atoms in the alkyl chain, is sulfonated, e. g., with an excess of fuming sulfuric acid, and then neutralized with sodium hydroxide or sodium carbonate to form an aqueous solution or slurry of the corresponding sodium salts which are subsequently converted to the desired solid particles by a drying treatment such as spraydrying or drum-drying.

It is a common practice to leave all or a part of un reacted sulfuric acid in the sulfonation reaction mixture so as form upon neutralization an aqueous slurry or dispersion of sodium alkyl benzene sulfonates and sodium sulfate. The presence of this latter inorganic salt does not diminish the detergent power of the sulfonate, but,

2,709,687 Fatented May 31, 1955 on the contrary, exerts a desirable effect on the detergency of the sulfonate. In fact, additional sodium sulfate or other inorganic builders, e. g., sodium silicate and particularly the phosphates such as sodium tripolyphosphate or tetrasodium pyrophosphate, are frequently incorporated into the slurry prior to the drying thereof in order to make up the desired active detergent to builder ratio in the final solid particulate product. In addition, minor amounts of a detergency promoter, e. g., from 1 to 5% by weight of sodium carboxymethyl cellulose, perfume, optical bleach, etc, may be present in the detergent composition.

Another type of alkyl benzene sulfonate detergent composition which can be stabilized against caking in accordance with this invention is one containing as its active ingredient a sulfonate material produced by condensing benzene with a chlorinated kerosene fraction, sulfonating with a suitable sulfonation agent, neutralizing with sodium hydroxide or sodium carbonate and drying to the desired particle-form.

As stated hereinbefore, sodium salts of saturated aliphatic sulfonic acids having from 1 to 6 carbon atoms in the hydrocarbon portion thereof are effective additives for the prevention or reduction of caking in accordance with our invention in detergent compositions containing in each 100 parts by Weight thereof from about 10 to about parts by weight of sodium C9 to C12 monoalkyl benzene sulfonate as their active detergent constituent. These salts, as we pointed out before, may be derived from alkane sulfonic acids as Well as from cycloalkane sulfonic acids. These salts are added to the detergent compositions in amounts which range from about 0.5 to about 10.0% by weight, based on the total composition, amounts from about 1.0 to about 5.0% by weight being preferred. The presence of these small quantities of sodium C to C6 saturated aliphatic sulfonates in a sodium alkyl benzene detergent decreases the extent of caking markedly. Particularly effective reduction of caking is obtained with compositions containing from about 20 to about 60 parts by weight of sodium C9C1s monoalkyl benzene sulfonate detergent, the remainder of the total of parts by weight being sodium sulfate and/ or other suitable builder.

Several different methods may be employed to incorporate the caking preventive agents of our invention into the alkyl benzene detergent compositions. One method consists in adding sodium salts of saturated aliphatic sulfonic acids (sodium alkane sulfonates) to the neutralized slurry of sodium C9 to Cis alkyl benzene sulfonate together with other additives and builders which may be required, whereupon the slurry containing all these additives can be dried and reduced to the desired particleform.

The preferred method of incorporating the anti-caking 1 additive consists in dissolving or dispersing sodium salts of saturated aliphatic sulfonic acids of our invention or the corresponding free alkane sulfonic acids in the neu tralizing reagent, such as a caustic soda solution or sodium carbonate solution, which is to be employed for neutraliz ing the mixture of C9-C1& alkyl benzene sulfonic and unreacted sulfuric acids. In some instances, one may also add the caking preventive by first adding a saturated aliphatic sulfonic acid to the sulfonation mixture of (39-018 alkyl benzene sulfonic acids and unreacted sulfuric acid, whereupon the whole mixture is neutralized and dried. Furthermore, one may prepare our caking preventives by adding C1 to C6 alkane sulfonic acids to the mixture of Cs-Cis alkyl benzenes, and subsequently sulfonating and neutralizing; or yet C1 to C6 alkane sulfonic acids may be added to the sulfuric acid about to be used for the sulfonation of C9 to C18 alkyl benzenes.

In order to test the magnitude of the anti-caking or caking-preventive efiect of sodium salts of C1 to C6 saturated aliphatic sulfonic acids in detergent compositions containing sodium C9C1s alkyl benzene sulionates as their active ingredient, a number of samples of such compositions were prepared and subjected to caking tests in a humidity cabinet in accordance with the follow ing procedure:

Weighed 100 g. samples of dried compositions screened through a #16 sieve and collected on a #4 sieve were placed in small untreated sealed cardboard boxes (l /2 x 2 /2 x 4"). Three samples of each composition containing sodium salts of saturated aliphatic sulfonic acids, together with three control samples containing no such salts were placed in a random manner in a humidity cabinet and continuously exposed therein to a relative humidity of about 80% at a temperature of about 90 F. The exposure period lasted seven days. At the termination of this period the boxes with samples were taken out, reweighed, and the extent of caking was determined by cutting away an entire side of each cardboard box and carefully transferring its contents onto a #4 sieve 4" mesh) from a minimum height. The sieve was then gently swirled and tipped until all particles came into contact with the screen. The material which did not pass through the screen by this tipping and swirling was considered to be caked, and the ratio of its weight to the weight of the original sample was designated as Per Cent of Material Caked.

The following Table I contains the results of a number of representative test runs carried out on samples of a typical alkyl benzene sulfonate detergent composition, namely, one containing sodium GTE-C polypropylene benzene sulfonate prepared in accordance with the procedure described in U. S. Patent No. 2,477,383, issued to A. H. Lewis. This sulfonate was prepared by polymerizing propylene to form a mixture of C12 to C15 polypropylene, alkylating benzene with the resulting polypropylene product in the presence of hydrofluoric acid as a catalyst, sulfonating the so produced mixture of alkyl benzenes, and neutralizing the sulfonation reaction mixture with caustic soda, whereupon the neutralized aqueous dispersion or slurry of sulfonates and sodium sulfate was dried to small particles, following the incorporation of the caking preventive of our invention in accordance with the preferred method described hereinabove.

TABLE I a small amount from about 1.0 to about 5.0% by weight of sodium salts of C1 to C6 saturated aliphatic sulfonic acids into detergent compositions having as their active ingredient sodium salts of C12-C51 monoalkyl benzene sulfonic acids, a remarkable reduction of the tendency of these compositions to cake is obtained.

it is to be understood that the aforegiven description and experimental data merely illustrate our invention which is not limited thereby, but only by the definitions the appended claims.

We claim:

1. A solid, particle-form nOn-caking detergent composition which contains in each 100 parts thereof from about 10 to about 95 parts by weight of sodium salts of monoalkyl benzene sulfonic acids having from 9 to 18 carbon atoms in the alkyl chain, the remainder of said 100 parts being essentially inorganic sodium salt builders and from about 0.5 to about 10% by weight of sodium salts of saturated aliphatic sulfonic acids containing from 1 to 6 carbon atoms in the aliphatic portion thereof, based on the combined weight of the detergent and builder ingredients.

2. A solid, particle-form non-caking, dry detergent composition which contains in each 100 parts thereof from about 10 to about 95 parts by weight of sodium salts of monoalkyl benzene sulfonic acids having from 9 to 18 carbon atoms in the alkyl chain, the remainder of said 100 parts being essentially sodium sulfate builder and from about 0.5 to about 10% by weight of sodium salts of saturated aliphatic sulfonic acids containing from i to 6 carbon atoms in the aliphatic portion thereof, based on the combined weight of the detergent and builder ingredients.

3. A solid, particle-form non-caking detergent composition which contains in each 100 parts thereof from about 10 to about 95 parts by weight of sodium salts of monoallryl benzene sulfonic acids having from 9 to 18 carbon atoms in the alkyl chain, the remainder of said 100 parts being essentially inorganic sodium salt builders and from about 0.5 to about 10% by weight of sodium salts of saturated aliphatic sulfonic acids wherein the aliphatic portion contains an average of two carbon atoms, based on the combined weight of the detergent and builder ingredients.

4. A solid, particle-form non-eaking, dry detergent Results of coking determinations after 7 days in the humidity cabinet Composition of Formulation viiiiiii i Methtm of Method of ii eitiiiiiii Test sodium Percent; Percent adding prematerials 35 2121 Calring preventive added g gtif tion wnnvc 353522 pylene sulfate ventive benzene sulfonate 1 40 60.0 Drum-dried 2 40 50.0 Mixture of sodium salts 1.0 do t To NaOH. 10

of C C C saturated aliphatic sultonates (aver. mol. wt. of sodium ethane suh'onate). 40 57.0 d0 3.0 l 40 55.0 .(1o 5.0 l. 40 57.0 Sodium n-butaue sulfo- 3.0 27

nuts. 40 55.0 do 5.0 11 40 50.0 Sodium cyclohexane sul- 1.0 20

fonate. 40 57.0 do 3.0 do d0 7 40 55.0 do 5.0 do tlo .i

Similar results are obtained if tetrasodium pyrophosphate, or sodium tripolyphosphate is substituted in part or entirely for the sodium sulfate in the above-identified detergent composition.

The data tabulated in Table I show that by incorporating composition which contains in each 100 parts thereof from about 10 to about parts by weight of sodium salts of monoalkyl benzene sulfonic acids having from 9 to 18 carbon atoms in the alkyl chain, the remainder of said parts being essentially inorganic sodium salt builders and from about 0.5 to about 10% by weight of sodium butane sulfonate, based on the combined weight of the detergent and builder ingredients.

5. A solid, particle-form non-caking detergent composition which contains in each 100 parts thereof from about 10 to about 95 parts by weight of sodium salts of monoalkyl benzene sulfonic acids having from 9 to 18 carbon atoms in the alkyl chain, the remainder of said 100 parts being essentially inorganic sodium salt builders and from about 0.5 to about 10% by weight of sodium cyclohexane sulfonate, based on the combined weight of the detergent and builder ingredients.

6. A solid, particle-form non-caking, dry detergent composition which contains in each 100 parts thereof from about 10 to about 95 parts by weight of sodium salts of polypropylene benzene sulfonic acids containing from 12 to 15 carbon atoms in the polypropylene chain, the remainder of said 100 parts being essentially inorganic sodium salt builders and from about 0.5 to about 10% by weight of sodium salts of saturated aliphatic sulfonic acids containing from 1 to 6 carbon atoms in the aliphatic portion thereof, based on the combined weight of the detergent and builder ingredients.

7. The method of inhibiting caking of solid, particle form detergent compositions containing in each 100 parts by weight thereof from about 10 to about 95 parts by weight of sodium salts of monoalkylbenzene sulfonic acids having from 9 to 18 carbon atoms in the alkyl chain, the remainder to make up 100 parts being essentially inorganic sodium salt builders, said composition normally exhibiting a tendency to cake when stored in a Warm, humid atmosphere, said method comprising forming an aqueous slurry of said sodium monoalkylbenzene sulfonates and said inorganic sodium salt builders, having intimately mixed therein from about 0.5 to about 10 per cent by Weight of sodium salts of saturated aliphatic sulfonic acids containing from 1 to 6 carbon atoms in the aliphatic portion thereof, based on the total solid content of said slurry, and spray-drying this slurry.

References Cited in the file of this patent UNITED STATES PATENTS 2,477,383 Lewis July 26, 1949 

1. A SOLID, PARTICLE-FORM NON-CAKING DETERGENT COMPOSITION WHICH CONTAINS IN EACH 100 PARTS THEREOF FROM ABOUT 10 TO ABOUT 95 PARTS BY WEIGHT OF SODIUM SALTS OF MONOALKYL BENZENE SULFONIC ACIDS HAVING FROM 9 T 18 CARBON ATOMS IN THE ALKYL CHAIN, THE REMAINDER OF SAID 100 PARTS BEING ESSENTIALLY INORGANIC SODIUM SALT BUILDERS AND FROM ABOUT 0.5 TO ABOUT 10% BY WEIGHT OF SODIUM SALTS OF SATURATED ALIPHATIC, SULFONIC ACIDS CONTAINING FROM 1 TO 6 CARBON ATOMS IN THE ALIPHATIC PORTION THEREOF, BASED ON THE COMBINED WEIGHT OF THE DETERGENT AND BUILDER INGREDIENTS. 